The National Weather Service Storm Prediction Center has issued a Severe Thunderstorm Watch for Philadelphia and surrounding counties until 9 p.m.
This watch means that conditions are favorable for thunderstorms containing 1 inch or larger hail and/or wind gusts of at least 58 mph (50 knots). Persons in the watch area should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes.
An Extreme Heat Warning for the Philadelphia area expires Friday (6/22/12) at 5 p.m.